Functional conservation of wheat orthologs of maize rough sheath1 and rough sheath2 genes
Functional conservation of wheat orthologs of maize rough sheath1 and rough sheath2 genes
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DOI：
10.1007/s11103-008-9422-5
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发表时间：
2009-02
影响因子：
5.1
通讯作者：
R. Morimoto;Emi Nishioka;K. Murai;S. Takumi
中科院分区：
文献类型：
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作者：
R. Morimoto;Emi Nishioka;K. Murai;S. Takumi
MaizeroughSheath2(RS2)和拟南芥ASYMMETRIC LEAVES1(AS1)都编码Myb转录因子并抑制Knox基因。玉米和拟南芥之间的RS2/AS1-KNOX关系在功能上是保守的。在此，我们克隆了小麦RS2/AS1和玉米粗鞘1(Rs1)KNOX基因的同源基因，分别命名为WRS2和WRS1。WRS1mRNA在营养枝分生组织的叶片插入点检测到，但在分化的花器官中缺失。相反，WRS2转录本在花器官的起始和发育中积累。表达WRS1的转基因烟草植株由于表达其他KNOX基因而表现出典型的形态变化。Myb结构域缺失的WRS2可以与NtPHAN相互作用形成异源二聚体，而主干WRS2基因的表达赋予了与预期和诱导的内源KNOX基因的异位表达相似的显性-负表型。此外，WRS2的表达减轻了表达小麦KNOX基因的烟草植株的形态变化。因此，WRS2基因产物抑制了KNOX的表达。这些结果表明，WRS2-KNOX关系在小麦发育过程中分生组织侧器官的分化和分化中起着重要的作用。小麦分生组织周围的WRS2和KNOX之间的拮抗关系在小麦进化过程中一直是功能保守的。
Maizeroughsheath2(RS2) andArabidopsisASYMMETRIC LEAVES1(AS1) both encode a Myb transcription factor and repressKnotted1-type homeobox (KNOX) genes. The RS2/AS1-KNOX relationship is functionally conserved between maize andArabidopsis. Here, we cloned wheat orthologs ofRS2/AS1and of a maizeroughsheath1(rs1)KNOXgene and named themWRS2andWRS1, respectively.WRS1mRNA was detected at leaf insertion points of the vegetative shoot meristem but was missing in differentiating floral organs. Conversely,WRS2transcripts accumulated in initiating and developing floral organs. Transgenic tobacco plants expressingWRS1showed morphological alterations typically observed due to expression of otherKNOXgenes.WRS2with a deletion of the Myb domain could interact with NtPHAN to form a heterodimer, and expression of the truncatedWRS2gene conferred a dominant-negative phenotype similar to that expected and induced ectopic expression of an endogenousKNOXgene. Moreover,WRS2expression alleviated morphological alterations in tobacco plants expressing the wheatKNOXgene. Therefore, theWRS2gene product repressesKNOXexpression. These results indicate that theWRS2–KNOXrelationship plays a fundamentally important role in lateral organ initiation and differentiation of meristems in wheat development. The antagonistic relationship betweenWRS2andKNOXaround meristematic tissues has been functionally conserved during wheat evolution.